1. Technical Field
The present invention relates to a method of forming a mask and a mask, and in particular, to a method of forming a film adapted to film formation by deposition and a mask.
2. Related Art
In manufacturing a large-sized full color organic electroluminescent (EL) panel used in a TV display, a highly precise deposition mask is needed and the deposition mask must be precisely aligned with a substrate to be filmed so as to be deposited. Conventionally, a metal mask made of very thin galvanoplastics has been widely used to manufacture the full color organic EL panel. Due to the metal mask having high flexibility, the metal mask must be bonded to a mask holding frame with tension so as to be used in the panel. However, it is difficult to manufacture a highly precise mask since dimensions of the mask become too large due to plastic deformation occurring when the tension is applied. Thus, a producible size of the full color organic EL panel using the metal mask has a limitation of 20 inches or so, which is realized in the present condition.
In order to overcome such a limitation, a technique of using a silicon wafer having very high substrate strength and excellent flatness has been studied. In addition, since the silicon substrate itself has no large substrate, a technique of precisely aligning the silicon mask with a large frame to obtain a deposition mask corresponding to the large substrate has been proposed (for example, see JP-A-2001-237073).
However, since the mask becomes heavier as it becomes larger in size, it may warp due to its own weight. As a result, even though the substrate is aligned with the mask, a gap between the substrate and the mask may occur due to the bend, which may result in an incorrect mask patterning.